The present invention relates generally to enclosures for electronic equipment and, more particularly, to a micro-cabinet or vault that facilitates the underground storage of electronic equipment, such as instrumentation for wireless telecommunications transceiver systems.
Public demand for wireless telecommunications has grown at a tremendous rate. An increasing number of people rely on their wireless phones for an increasing number of uses including voice, messaging, data, video, and internet access. This enormous public demand has in turn fueled the need for additional carrier antenna sites to provide expanded wireless coverage to communities.
As the need for additional antenna sites has grown, so too has the installation restrictions set by many municipalities. Cell phone carriers are being required to place their transceiver equipment in an aesthetically pleasing manner. In many municipalities the planning departments are unwilling to grant permit applications for unsightly tower installations. There is also a growing tendency for many of these municipalities to require even the smallest of transceiver circuitry units to be placed underground, and for the antennas to be disguised or stealthed.
A partial, but elegant, solution for many carriers has been to disguise their antennas by placing them atop of street light standards or other vertical structures, such as signs, etc., along existing right of ways. However, no such solution is currently available to cell phone carriers for burying their transceiver circuitry.
The units housing the transceiver or transmitting and receiving circuitry for wireless telecommunications systems come in different sizes, and have different power and transceiver configurations. The standard or xe2x80x9cmacro-cellxe2x80x9d unit is a compact base transceiver station (xe2x80x9cBTSxe2x80x9d), which stores six (6) to eight (8) transceivers or radios requiring 1800 to 2200 watts of power. The smallest unit currently used, primarily where a mono-pole transceiver system is inappropriate, is a xe2x80x9cmicro-cellxe2x80x9d, which typically houses one (1) to two (2) transceivers requiring 170 to 600 watts of power. Currently, the vaults available to place the compact BTS""s or micro-cells underground tend to be too large to be useful in right of way applications many carriers are looking to implement. Typically these vaults are made of concrete, which for strength and equipment security reasons require thick walls and considerable overall size. Because of their overall size, there are limits as to where these vaults can be placed.
In addition, the problem with any self-contained, sealed underground vault is that the telecommunications equipment enclosed therein generates heat, which ultimately damages or destroys the equipment. Moisture, either from evaporation or flooding from rain, can also damage or destroy the equipment. These problems are typically solved by using an air conditioner and dehumidifier in conjunction with a water pump, which add to the complexity and cost of the vault. Most existing vaults include an unattractive heat exchanger that is located above ground, or an underground heat exchanger that is quite costly to construct and install, and adds to the overall space needed to bury the vault.
Thus, it would be desirable to provide the wireless telecommunications industry with a vault to house micro-cells underground that is considerably smaller in size without sacrificing strength or security, and which maintains proper climate control for equipment longevity without cost or aesthetically prohibitive heat exchangers.
The present invention is directed to an improved vault or cabinet for storage of electronic equipment, such as wireless telecommunications equipment, underground in public right of ways. In a particularly innovative aspect of the invention, the micro-cabinet of the present invention is formed of a metal weldment, preferably stainless steel, which enables it to be made comparatively small without sacrificing strength or equipment security. Because of its reduced overall size, the micro-cabinet can easily be placed in a public right of way.
In another innovative aspect of the present invention, the micro-cabinet is substantially water-tight with a self contained cooling system and a water evacuation system. The water evacuation system preferably utilizes a one-way pressure actuated exhaust valve that enables the cabinet to be submerged in water with no danger to the enclosed equipment. Alternative cooling systems utilize similar one-way valves or snorkel-type piping running up an existing vertical structure along the public right of way.
In yet another innovative aspect of present invention, the micro-cabinet includes a weight or spring assisted rack for storage of transceiver equipment in the cabinet. The weight or spring assist system provides easy access to the stored electronic equipment when maintenance or repairs are necessary. In addition, the rack is preferably constructed to act as an internal support or brace for the micro-cabinet to further enhance the cabinet""s overall structural integrity.
In a further innovation aspect of present invention, the micro-cabinet is preferably buried in a public right of way adjacent an existing vertical structure such as a light standard or sign. Cabling runs from the transceiver circuitry within the cabinet up along the interior or exterior of the vertical structure to an antenna positioned on top of the vertical structure. Unlike conventional designs, the vault or micro-cabinet of the present invention can be placed in virtually any city, under any existing vertical structure, e.g., a light standard, which is mounted on or near a sidewalk, while being fully disguised, and tending to pose no hazards to pedestrians.
In yet another innovative aspect, a cooling system of the present invention tends to eliminate the need for an electric powered air conditioner and dehumidifier, which tends to significantly reduce costs and advantageously enables the micro-cabinet to be dramatically smaller than most other telecommunication vaults. The cooling system of the present invention also advantageously enables a generator to be placed within the micro-cabinet, which ordinarily would be infeasible due to the cooling requirements of the generator.
In a preferred embodiment, the cooling system comprises a separate compartment attached to the end of the micro-cabinet, sharing a common wall. An opening or cooling vent is positioned toward the top of the common wall to allow hot air and moisture to vent from the micro-cabinet to the separate compartment. The separate compartment has air vents on the top, exposed to surface air, and louvered so that rain or water entering the separate compartment cannot fall through the opening in the common wall. These air vents allow heat and moisture to escape from the vault. A closure system comprising a door and a flotation device is provided to seal the cooling vent in the common wall. The door is mounted in moveable relation to the common wall and the flotation device, which causes the door to rise and seal the cooling vent as water fills the separate compartment, is operably coupled to the door.
Other innovative aspects of the invention include the preceding aspects individually or in combination.
Other aspects and features of the present invention will become apparent from consideration of the following description taken in conjunction with the accompanying drawings.